Body control module manages diverse vehicle functions

The number of electronic devices entering vehicles is increasing. Accordingly, they perform various roles including safety, driver assistance, and information provision. The body control module (BCM) controls various functions within the vehicle through signals.

This module manages various vehicle functions including door locks, chime control, interior/exterior lighting, security functions, wipers, turn signals, and power management. Connected to the vehicle's electronic architecture, the BCM reduces multiple plug-in contacts and cable harnesses while providing maximum reliability and cost-effectiveness.

As demand for diverse BCM functions grows, the amount of cable harness is also increasing. According to Kiyotsugu Oba's "Wiring Harness for Next-Generation Vehicles," the total weight of wiring harnesses using general electronic wires in compact vehicles today reaches approximately 30 kg, whereas in the 1970s it was only a few kilograms. The BCM reduces the amount of wiring in vehicles by providing an interface for bus systems, significantly lowering costs. Approximately 80% of the product budget is determined at the BOM stage, that is, in the early development phase.

The BCM market trend is centralization. This is because centralized architecture supports many functions with fewer modules than distributed architecture. The advantages of centralized architecture are simplified networking, high cost efficiency, and optimization of the complete control unit (ECU) that reduces harness weight. Weight reduction not only lowers manufacturing costs but also improves fuel efficiency, benefiting both manufacturers and consumers.

Meanwhile, centralized architecture is causing microcontrollers (MCUs) to suffer from insufficient input/output (I/O) for connecting switches and sensors within the vehicle. For complex design architectures, 60 to 120 switch connections are required to the central BCM. One method to solve this problem is to add discrete components to provide I/O. However, in this case, more components are needed in board design, and the cost savings from reduced wiring are offset by electronic device costs.

Using integrated MSDI solutions such as TI's TIC12400-Q1 or TIC10024-Q1 detects the opening and closing of 24 to 56 switch contacts as shown in Figure 1.

MSDI devices use integrated analog-to-digital converter (ADC) / comparators to detect external switch status and report it to the MCU. The main difference between TIC10024-Q1 and TIC12400-Q1 is that TIC12400-Q1 has switch matrix polling capability and integrated ADC, capable of handling analog and multiple threshold values.

Devices such as TIC10024-Q1 and TIC12400-Q1 can eliminate up to 120 components

TIC10024-Q1 and TIC12400-Q1 also include electrostatic discharge (ESD) protection (±8kV), reverse battery protection, and transient pulse protection functions. Since external protection components are unnecessary, BOM costs and board size are reduced. Additionally, by reducing hardware and software complexity, reliability is enhanced while scalability enables use in low-end, mid-tier, and high-end platforms.


MSDI devices integrate intelligent functions that perfectly meet BCM trends, enabling integration of comfort electronics without significant cost.